Pollen diagrams from four sites in Northumberland have been produced in order to study the impact of prehistoric man on the vegetation of the region since Neolithic times. The major vegetational changes have been radiocarbon dated at Fellend, Steng and Camp Hill Mosses, but not at Broad Moss.

There is evidence at all four sites for small temporary clearances in the woodlands during the Bronze Age and also during the pre-Roman Iron Age. These clearances were mainly for grazing and their frequency at a site accords well with the archaeological evidence for settlement.

All the diagrams show a major clearance of forest, primarily for pasture, dated at Fellend and Steng Mosses to the time of the Roman occupation of the north-east of England. At Camp Hill this clearance gave a late medieval date, but there is good reason for suspecting the sample may have been contaminated with 14C-rich carbon. Regeneration of forest occurred some one to two hundred years after the withdrawal of the Romans. This has also been observed on diagrams from neighbouring counties, and indicates a post-Roman period of economic stability.

There was a further extensive clearance, dated at Fellend and Steng Mosses to the time of the Scandinavian settlement, and the diagrams show a late medieval recession in farming and a regeneration of woodland before the present landscape was created.

Rates of peat accumulation were estimated from the radiocarbon dates at Fellend Moss, where it increased in late medieval times, and at Steng Moss, where it did so in the late Bronze Age.